The present invention relates to a golf club head. More particularly, the present invention relates to an iron-type golf club head in which a viscoelastic body is adherently disposed on the back face of a face plate part. Still more particularly, the present invention relates to a golf club head in which a viscoelastic body is made to adhere to a part of the outer face thereof, and a cover plate is provided so as to cover the viscoelastic body.
The iron-type golf club head includes at least a face plate part for hitting a ball, a sole part, and a hosel part. The golf club is formed by inserting and fixing a shaft in the hosel part.
To absorb a shock or vibrations occurring on the golf club head when a ball is hit by using the golf club, in some cases, a viscoelastic material such as rubber is made to adhere onto the golf club head, or is incorporated in a void of the golf club head.
JP 06-510689 T describes a golf club head in which an elliptical viscoelastic body that is made of butyl rubber or the like and has a major axis of 45 mm, a minor axis of 18 mm, and a thickness of 1 mm is bonded onto the back face of the face plate part, and also a 1-mm thick nameplate made of an aluminum-zinc-magnesium alloy is bonded onto the viscoelastic body.
This patent Document describes that the viscoelastic plate and the hard plate have the same size. Therefore, the whole of the end face of the viscoelastic plate is exposed to the atmospheric air, so that the viscoelastic plate is liable to be deteriorated by moisture or ultraviolet rays, or to peel off the back face of the face plate part. Also, since the viscoelastic plate absorbs vibrations propagating from the face plate part side only, the vibration absorbing action of the viscoelastic plate is sometimes insufficient.
To solve the above-described problems, JP 2011-30837 A discloses a golf club head of an iron type in which the durability of adhesion of the viscoelastic plate to the face plate part is excellent and which has a face plate part for hitting a ball, a sole part, and a hosel part for connecting a shaft thereto as a golf club head that has superior vibration absorbing effects. In this golf club head, a viscoelastic body is made to adhere to the back face of the face plate part, and a nameplate lapping over the viscoelastic body is provided, and it is characterized in that the nameplate has an expanding part expanding to the surroundings of the viscoelastic body, and the expanding part is made to adhere to the back face of the face plate part.
For the golf club head disclosed in this patent Document, the viscoelastic body is made to adhere to the back face of the face plate part, and further, the nameplate is provided so as to cover the viscoelastic body. The nameplate has the expanding part expanding to the surroundings of the viscoelastic body, and the expanding part is made to adhere to the back face of the face plate part. Therefore, the viscoelastic body is covered with the nameplate in an enclosed form, and is not exposed to the atmospheric air. For this reason, the viscoelastic body is not splashed with water, nor is it irradiated directly by ultraviolet rays, so that the durability of the viscoelastic body and the durability of adhesion of the viscoelastic body to the back face of the face plate part are excellent.
Also, in this patent Document, since the expanding part of the nameplate is made to adhere to the face plate part, some of the vibrations occurring in the peripheral edge portion of the face plate part at the ball hitting time (shot time) propagates to the viscoelastic body via the nameplate and is absorbed by the viscoelastic plate.